The industrial fields related to vehicles or construction materials that are mostly exposed to the external environment need a composite having a high level of toughness. Particularly, this is the more so as external automobile parts such as rare beams, seat backs, and under covers that are exposed to the external impact.
In this regard, since a degree to stand and resist against the force of an applied impact is the most important factor of the composite and an essential standard factor for the composite to be used as a component, the two most important factors that influence toughness of the composite are strength and elongation (a degree of extension). The two factors contradict each other, where a composite having a high strength is hard that may be easily break and thus may have a low elongation, and a relatively soft composite has a high elongation but may not have a high strength. Therefore, various studies to manufacture a composite having both high strength and excellent elongation have been conducted.
Also, a need for a composite having good functionalities such as electric conductivity, thermal conductivity, and transparency as well as good physical properties has increased.